Cervix (plural: cervices) is a fibromuscular organ that connects the vagina with the uterine cavity, forming the lower part of the uterus. Sometimes called the “neck of the uterus,” the cervix plays an important role in allowing fluids to pass between the uterus and vagina. The human female cervix has been documented anatomically since at least the time of Hippocrates, over 2,000 years ago. The Latin word cervix was used to translate the Greek word αὐχήν (auchḗn), meaning “neck”.
Cervix
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| Category | Reproductive Anatomy, Gynecology |
| Research Fields | Obstetrics & Gynecology, Oncology, Pathology |
| Also known as: | Uterine cervix, neck of the uterus |
| Pronunciation: | SUR-viks |
| Dimensions: | 4 cm long, 3 cm diameter |
| Main components: | Ectocervix, endocervix, internal/external os |
| Primary functions: | Menstruation, fertility, pregnancy, childbirth |
| Common conditions: | HPV infection, cervical cancer, dysplasia |
| Key screening: | Pap smear, HPV testing |
History
Ancient Times: First Anatomical Documentation
The cervix was documented in anatomical literature at least during the time of Hippocrates, with cervical cancer first described more than 2,000 years ago by both Hippocrates and Aretaeus. Ancient physicians recognized the cervix as a distinct anatomical structure, though their understanding of its functions was limited.
1500s-1600s: Renaissance Anatomical Studies
During the Renaissance, improved anatomical dissection techniques led to more detailed understanding of cervical structure. Medical texts began distinguishing between different parts of the female reproductive system, including more precise descriptions of cervical anatomy and its relationship to surrounding organs.
1800s: Clinical Recognition and Disease Description
The 19th century marked significant advances in understanding cervical pathology. Physicians began recognizing various cervical conditions and developing early therapeutic approaches. The relationship between cervical disease and reproductive health became better understood through clinical observation.
1920s-1940s: Pap Smear Development
Dr. George Papanicolaou developed the Pap smear test in the 1920s, though it wasn’t widely adopted until the 1940s and 1950s. This revolutionary screening method enabled early detection of cervical abnormalities and dramatically reduced cervical cancer mortality in countries with organized screening programs.
1950s-1970s: Cancer Prevention Programs
Since the 1950s, the death rate from cervical cancer has decreased by as much as 70%, primarily in high-income countries due to screening programs. Mass screening initiatives were implemented in developed nations, leading to significant reductions in cervical cancer incidence and mortality.
1980s-1990s: HPV Discovery and Understanding
Harald zur Hausen’s groundbreaking research in the 1980s established the link between human papillomavirus (HPV) and cervical cancer, earning him the 2008 Nobel Prize in Physiology or Medicine. This discovery revolutionized understanding of cervical cancer etiology and paved the way for prevention strategies.
2000s: HPV Vaccine Development
In 2006, HPV vaccine was first recommended in the United States to prevent cancers and other diseases caused by HPV. The introduction of preventive HPV vaccines marked a new era in cervical cancer prevention, offering protection against the primary cause of cervical cancer.
2010s: Improved Screening Technologies
HPV DNA testing was increasingly incorporated into cervical screening programs, either as primary screening or co-testing with Pap smears. HPV testing was introduced as a triage test in 18 countries, with six countries announcing plans for HPV-based primary screening by 2024.
2020s: WHO Elimination Initiative
The WHO Global strategy defines elimination as reducing new cases to 4 or fewer per 100,000 women annually, with targets of 90% HPV vaccination coverage, 70% screening coverage, and 90% treatment of cervical disease by 2030. Recent data shows significant decreases in cervical precancer incidence, with 79% reduction among women aged 20-24 years from 2008-2022.
Anatomy and Structure
Location and Position
The cervix is located inside the pelvic cavity, anywhere from 3 to 6 inches inside the vaginal canal, beginning at the base of the uterus and extending downward onto the top part of the vagina. The cervix lies between the bladder anteriorly and the bowel posteriorly, with the ureters in close proximity laterally.
Anatomical Components
The cervix comprises two main regions: the ectocervix and endocervical canal, containing two openings called the external os and internal os. The ectocervix is the portion that projects into the vaginal lumen and is lined by non-keratinized stratified squamous epithelium. The endocervix (endocervical canal) extends from the external os to the internal os, where it opens into the uterine cavity.
Transformation Zone
The transformation zone is the area where squamous epithelium meets columnar epithelium at the squamocolumnar junction, which is dynamic and moves during adolescence and pregnancy. This zone is particularly important because it’s where most cervical cancers and precancerous changes occur.
Histological Features
The endocervical canal is lined with a moist mucous membrane containing cells that secrete fluids and project minute hairlike structures called cilia that help move sperm through the canal. Covering the mucous membrane is a thick layer of collagen and elastic fibers, with some muscle tissue, making the cervix more rigid than other uterine tissue.
Functions
Menstrual Function
The cervix allows period blood to pass from the uterus through the cervix before exiting the vagina during menstruation. The cervical canal allows blood to flow from the uterus through the vagina at menstruation, which occurs in the absence of pregnancy.
Fertility and Reproduction
Cervical mucus plays a role in fertility – around ovulation, the cervix secretes mucus that’s thinner and less acidic than usual, making it easy for sperm to pass through to the uterus. During ovulation, mucous secretions are plentiful and watery, while before and after ovulation the secretions are thick and relatively scant.
Pregnancy and Childbirth
During pregnancy, the cervix secretes a mucus plug that seals entry to the uterus, and during childbirth, the mucus plug dissolves and the cervix becomes softer, thinner, and widens (dilates) so the baby can exit the uterus. During pregnancy, the cervix is the only part of the uterus that does not expand to house the developing child.
Protective Function
The cervix prevents objects inserted into the vagina, such as tampons or diaphragms, from slipping inside the uterus. It forms a physical and immunological barrier that helps maintain sterility in the uterus through tight cervical closure, thick mucus, and periodic shedding of the endometrial lining.
Health Conditions
Human Papillomavirus (HPV) Infection
HPV is a common sexually transmitted infection that can affect the skin, genital area and throat, with almost all sexually active people being infected at some point. In 90% of people, the body controls the infection by itself, but persistent HPV infection with high-risk types causes cervical cancer. HPV is the cause of almost all cervical cancer and is responsible for a substantial fraction of other anogenital cancers.
Cervical Cancer
Globally, an estimated 660,000 new cervical cancer cases and around 350,000 deaths occurred in 2022. About 94% of the 350,000 deaths caused by cervical cancer occurred in low- and middle-income countries. In the United States, the rate of new cervical cancer cases was 7.7 per 100,000 women per year, with cancer most frequently diagnosed among women aged 35-44.
Cervical Dysplasia and Precancerous Changes
Cervical dysplasia refers to abnormal growth of cervical cells, often caused by HPV infection. Cervical precancers (cervical intraepithelial neoplasia grades 2-3 and adenocarcinoma in situ) can develop within a few years after HPV infection. These changes can be detected through screening and treated before progressing to cancer.
Cervical Insufficiency
Cervical insufficiency occurs when the cervix dilates too early in pregnancy, typically without contractions or pain, which can cause premature birth or miscarriage. This condition highlights the mechanical barrier role of the cervix, particularly the internal os, and can be managed with cervical cerclage.
Screening and Prevention
Cervical Cancer Screening
Women should be screened for cervical cancer every 5-10 years starting at age 30, with women living with HIV screened every 3 years starting at age 25. Globally, an estimated 370 million (36%) of 1 billion women aged 30-49 years have been screened for cervical cancer ever in their lifetime.
Screening Methods
Combined or alone, cytology (Pap smears) was the most used screening test, with 109 (78%) of 139 countries recommending it for at least one indication. 48 (35%) of 139 countries recommended primary HPV-based screening. Self-collection of samples for HPV testing has been shown to be as reliable as samples collected by healthcare providers.
HPV Vaccination
As of 2023, there are 6 HPV vaccines available globally, all protecting against high-risk HPV types 16 and 18, which cause most cervical cancers. HPV vaccines should be given to all girls aged 9-14 years, before they become sexually active, and may be given as 1 or 2 doses.
Global Health Impact
Disease Burden
The highest rates of cervical cancer incidence and mortality are in sub-Saharan Africa, Central America and South-East Asia. Cervical cancer is the #1 cause of death from cancer in women in 37 countries, with 29 of those countries in sub-Saharan Africa. About 90% of new cervical cancer cases and deaths worldwide in 2020 occurred in low- and middle-income countries.
Health Disparities
Regional differences in cervical cancer burden are related to inequalities in access to vaccination, screening and treatment services, risk factors including HIV prevalence, and social and economic determinants. Women living with HIV are 6 times more likely to develop cervical cancer compared to the general population.
Prevention Progress
Among women aged 20-24 years who were screened, rates during 2008-2022 decreased for cervical precancer by 79%, consistent with considerable impact of HPV vaccination. Modelling estimates that 74 million new cases of cervical cancer can be averted and 62 million deaths avoided by 2120 by reaching WHO elimination goals.
Research and Future Directions
Improved Screening Technologies
Research continues on developing more accessible and cost-effective screening methods, including point-of-care HPV testing and artificial intelligence-assisted cytology interpretation. Self-sampling methods are being refined to increase screening uptake in underserved populations.
Vaccine Development
Next-generation HPV vaccines are being developed to provide broader protection against additional HPV types and potentially require fewer doses. Research also focuses on therapeutic vaccines for treating existing HPV infections and cervical lesions.
Global Elimination Efforts
Implementation research examines strategies for scaling up prevention programs in low-resource settings. Studies investigate optimal delivery methods for vaccination, screening, and treatment services to achieve WHO elimination targets by 2030.
Frequently Asked Questions
What is the difference between the cervix and the uterus?
The cervix is the lower, narrow part of the uterus that connects to the vagina. While the uterus is the larger organ where a fetus develops during pregnancy, the cervix acts as a gateway between the uterus and vagina, controlling what enters and exits the uterus.
How often should I have cervical screening?
Most women should begin cervical screening at age 21-25 (depending on country guidelines) and continue every 3-5 years depending on the test used. Women with HIV or other risk factors may need more frequent screening. Consult your healthcare provider for personalized recommendations.
Can HPV vaccination prevent all cervical cancer?
HPV vaccines prevent infection with the most common cancer-causing HPV types (16 and 18), which cause about 70% of cervical cancers. Newer vaccines protect against additional types. However, regular screening remains important even after vaccination for comprehensive protection.
What happens to the cervix during pregnancy and childbirth?
During pregnancy, the cervix remains tightly closed and produces a mucus plug to protect the developing baby. As labor approaches, hormonal changes cause the cervix to soften, thin out (efface), and gradually open (dilate) to allow the baby to pass through during delivery.
What are the symptoms of cervical problems?
Many cervical conditions, including early cervical cancer, often cause no symptoms. Possible signs include unusual vaginal bleeding (between periods, after sex, or after menopause), abnormal discharge, pelvic pain, or pain during intercourse. Regular screening can detect problems before symptoms develop.
Is cervical cancer preventable?
Yes, cervical cancer is largely preventable through HPV vaccination and regular screening. HPV vaccines can prevent infection with cancer-causing virus types, while screening can detect and treat precancerous changes before they become cancer.
What is cervical insufficiency?
Cervical insufficiency, also called incompetent cervix, occurs when the cervix opens too early during pregnancy without contractions or labor pains. This can lead to premature birth or pregnancy loss and may be treated with a surgical procedure called cerclage to keep the cervix closed.